The present invention relates to stud welding.
The art of stud welding is well known. The present invention is directed to that segment of the stud welding art employing a manual stud welding tool.
Prior art workers have devised a number of different types of stud welding tools, all of which operate in substantially the same manner. The tool operator manually mounts an individual workpiece on the electrode of the tool, which is typically in the form of a conical collet adapted to hold a workpiece. The operator then causes the tool to press the free end of the workpiece against a metallic surface at the position where the workpiece is to be mounted. Electrical current is applied to the workpiece, which is then slightly raised from the metallic surface to initiate an arc. The free end surface of the workpiece and the adjacent area of the metallic surface are rendered molten by the arc. The molten end of the workpiece is then again pressed against the molten surface, and then the electrical current is switched off. When the melt zone cools, the workpiece is welded to the metallic surface. The tool is then pulled from the workpiece and is ready to receive another workpiece.
Stud welding tools in the prior art are characterized by the fact that a given tool may be used with multiple sizes of workpieces. However, in a typical tool, to use a different size of workpiece, the electrode must be removed and replaced with an appropriately sized electrode to accommodate the new workpiece size. Furthermore, sliding friction from the cumulative effect of attaching multiple workpieces to the electrode wears the electrode mount. Eventually, the erosion necessitates replacement of the worn electrode. In addition, a conventional electrode can only accept workpieces having a simple geometry, such as a cylindrical threaded stud. Workpieces having flanges on the portion to be mounted to the electrode cannot be accepted without a special purpose electrode.
Thus, what is ideally desired is a device that can couple a workpiece having an arbitrary size or geometry and an electrode of a stud welding tool of a differing size or geometry for a welding operation while simultaneously reducing erosion of the tool due to sliding friction.
The present invention addresses these and other problems associated with the prior art by providing a disposable collet adapter for use with a manual stud welding tool so that workpieces of various sizes and geometries may be grasped for a subsequent welding operation.
A disposable collet adapter having features of the present invention comprises a hollow, elongate sleeve having a proximal open end and a distal open end. The collet adapter is adapted to couple a workpiece to an electrode of a stud welding tool. The proximal open end of the collet adapter is attachable in a readily releaseable fashion to an electrode of a stud welding tool. The distal open end of the collet adapter is releasably mounted to one end of the workpiece.
The cross-sectional profiles of the distal and proximal open ends of the disposable collet adapter are individually tailored to accommodate the corresponding cross-sectional profiles of the workpiece and electrode, respectively. As a result, the opposed open ends of the collet adapter can have divergent cross-sectional profiles. In addition, to facilitate use, either end of the collet adapter may include a flange.
The free end of the workpiece is fused to a metallic substrate in a welding operation as previously described. At one or both opposed ends, the workpiece will typically incorporate a fastening structure such as a shaped flange or a threaded surface.
If desired, a portion of the threaded end of the workpiece can be coated with a threadlocking chemical before or after a welding operation.
In a first mode of assembly, a single disposable collet adapter can be attached to the electrode and remain attached to mount a succession of workpieces having identical or similar ends. Alternatively, each workpiece can have its own collet adapter that remains attached to the workpiece following a welding operation.
The disposable collet adapter can be employed to couple the workpiece to the electrode of a stud welding tool having an automatic-feed mechanism. An automatic-feed stud welding tool can transport a succession of workpieces in a collating strip assembly into a position for a welding operation without individualized manual placement.
In a disclosed additional aspect, the invention provides an adapter for an automatic feed mechanism used in a stud welding tool. This adapter comprises an elongated insert sized for insertion into the feed mechanism to adapt the feed mechanism to fit a particular collating strip assembly.
An advantage of the disposable collet adapter is that a series of workpieces, each having a unique cross-sectional profile, can be welded without altering the electrode of the stud welding tool. The process of replacing the electrode of a stud welding tool is time-consuming and inconvenient. Another advantage is that the disposable collet adapter is an inexpensive construct that can be discarded after use. Yet another advantage is that the disposable collet adapter can intervene to prevent wear of the contacting surface of the electrode. When the electrode is prophylactically shielded by a disposable collet adapter, the frictional contact will occur between the contacting surfaces of the workpiece and collet adapter, not between the contacting surfaces of the workpiece and electrode.
These and other objects, advantages, features, and embodiments will be apparent with reference to the following drawings and detailed written description.